A unique tribute to the millions of animals who served and died for the British military.

This marine reptile was discovered by one of the 19th century's greatest fossil hunters.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

This hidden green space is the city's second largest conservatory.

The site of London's first coffee house has been serving refreshments of one kind or another for 360 years.

A little slice of Japan and its aesthetics in London's Holland Park.

This 1920s Dutch barge is now a floating bookstore.

Eighty million natural history specimens call this gargantuan museum home.

Originally meant to hold a statue of King William IV, this support sat empty for years. Today, it hosts a rotating cast of public artwork.

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

These coffin-like Brutalist balconies were inspired by a nearby mine.

The world's largest underground iron ore mine.

Indents in the pavement are all that remain from a grisly death machine in Paris.

The sculpture of the deceased cockatoo flops atop its personal plinth.

Sweden's oldest animated sign is still lighting up the skyline today.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

Small Easter eggs are hidden in the ventilation holes of the city's newest trains.

There are hidden patterns on the subway seats of some Stockholm metro cars.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

Stockholm's narrowest alley is barely over two feet wide.

Stockholm's tiniest statue is of a small boy looking at the Moon.

Hidden in plain sight, Sweden's official ordnance datum is now abandoned.

Stockholm's deepest subway station is also a stunning ecological wonder.

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.